JP2004028680A - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator offering various advantages such as a high-precision positioning resolution, a simpler structure and possibility of low-cost manufacturing. <P>SOLUTION: On a base 3 of this linear actuator 1, a main moving table 10 is mounted through a first linear guide 11. And on the main moving table 10, an accessory moving table 20 is mounted through a second linear guide 21. An accessory moving table driving mechanism 30 is provided with a 3rd linear guide 31, while a ball screw box 36 located between the 3rd linear guide 31 and the accessory moving table 20 is connected to both a motor 41 and a ball screw 45. When defining the traveling rate of the accessory moving table 20 as L, the traveling rate X of the main moving table 10 in a A direction is expressed as: X = L×tanθ, where tanθ≈0.1 at θ= approx. 6°. Therefore the movement (L) of the ball screw 45 moving the accessory moving table 20 can be reduced to 1/10 to be the movement (X) of the main moving table 10. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a linear actuator that can be applied to, for example, a table of a positioning device. In particular, the present invention relates to a linear actuator having advantages such as realizing high-precision positioning resolution, simple structure and inexpensive manufacturing.
[0002]
BACKGROUND ART AND PROBLEMS TO BE SOLVED BY THE INVENTION
2. Description of the Related Art As one type of image processing apparatus, there is known an image processing apparatus dedicated to positioning, which is used for bonding a thin film transistor (TFT) mask to glass and a screen printing machine. Such an image processing apparatus dedicated to positioning includes a table device for mounting and moving and positioning a mask, a screen, and the like. As a typical table device of this type, there is an XYθ table in which the table body can be moved in vertical and horizontal directions (XY directions) and in a rotational direction (θ direction).
[0003]
Such an XYθ table includes a table body on which a mask, a screen, and the like are placed, and a drive mechanism for driving the table body. The drive mechanism includes a guide that guides the table body, a motor that drives the table along the guide, and the like. The drive mechanism serves to support the table main body and move the table main body to a predetermined position in the XYθ direction for positioning.
[0004]
By the way, in recent years, the positioning dedicated image processing apparatus has been further refined. For example, with respect to the alignment of the above-described bonding between the TFT mask and the glass, it is required that the resolution be within the submicron level (0.1 μm). In response to the refinement of such devices, there is a demand for the above-mentioned table device capable of realizing high-precision positioning resolution.
[0005]
SUMMARY OF THE INVENTION The present invention has been made to meet the above-mentioned requirements, and has as its object to provide a linear actuator having advantages such as realizing high-precision positioning resolution, simple structure, and inexpensive manufacturing.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a linear actuator according to the present invention includes a base, and a main moving base mounted on the base so as to be movable in the A direction via a first linear guide (preload rolling linear bearing). A sub-mobile mounted on the main mobile via a second linear guide so as to be movable in the B direction with respect to the main mobile, and a third mobile mounted on the main mobile with respect to the base. A servo motor or a stepping motor that moves in the C direction via the linear guide of the above, and a sub-moving-table driving mechanism including a ball screw driven to rotate by the motor, and moves the sub-moving table in the C-direction. Thereby, the movable element of the second linear guide fixed to the sub movable table is moved in the direction B, and at the same time, the stator of the second linear guide fixed to the main movable table is moved to the A position. direction Then, the main moving table is moved in the direction A, and the moving amount L of the sub moving table in the direction C is reduced to a fraction or less to be the moving amount of the main moving table in the direction A. It is characterized by the following.
[0007]
According to the linear actuator of the present invention, for example, assuming that the B direction and the C direction are inclined by a small angle θ and the A direction and the C direction are made orthogonal, the movement amount of the main moving table in the A direction is Ltan tan θ. Become. Therefore, if the angle θ is set to about 6 °, tan θ ≒ 0.1, and the movement of the ball screw that moves the sub-moving stage can be reduced to 1/10 to be the movement of the main moving stage. For this reason, the positioning resolution of the main carriage can be kept at a submicron level.
Further, the preloaded linear guide (linear rolling guide bearing) has a low coefficient of friction and has no backlash, so that it is not only durable, but also realizes a straight operation without play with small power. In addition, since a so-called one-sided structure, which is required in a commonly used wedge-type operation reduction mechanism, is not required, the number of parts is small and the entire structure is simple.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, description will be made with reference to the drawings.
[First Embodiment]
FIG. 1 is a plan view showing a linear actuator according to the first embodiment of the present invention.
2A is a partially omitted left side view of the linear guide of FIG. 1, FIG. 2B is a front view, and FIG. 2C is a partially omitted right side view.
[0009]
As shown in FIGS. 1 and 2, the linear actuator 1 includes a flat base 3. On the base 3, a main moving table 10, a sub moving table 20, and a sub moving table driving mechanism 30 are mounted.
[0010]
The main carriage 10 is mounted on the base 3 via a first linear guide (preload rolling linear bearing) 11 (see FIGS. 2A and 2B). The first linear guide 11 is disposed on the base 3 along the left-right direction in FIG. The linear guide 11 includes a stator 12 fixed on the base 3 and a mover 13 slidably combined with the stator 12. The main carriage 10 is fixed on the mover 13 of the first linear guide 11. When the first linear guide 11 slides, the main moving base 10 can move in the A (and A ′) direction in FIG.
[0011]
The sub-mobile 20 is mounted on the main mobile 10 via a second linear guide 21 (see FIGS. 2A and 2B). The second linear guide 21 has a small angle θ counterclockwise in FIG. 1 with respect to a direction orthogonal to the AA ′ direction (sliding direction of the first linear guide 11) on the main moving base 10. (Approximately 6 degrees). The linear guide 21 includes a stator 22 fixed on the main moving base 10 and a mover 23 slidably combined with the stator 22. The sub carriage 20 is fixed on the mover 23 of the second linear guide 21. When the sub-mobile unit 20 is moved by the operation of the sub-mobile unit driving mechanism 30, the mover 23 of the second linear guide 21 also slides in the C (and C ') direction.
[0012]
The sub-mobile unit driving mechanism 30 is disposed on the base 3 on the right side in FIG. The sub-movement-table driving mechanism 30 includes a third linear guide 31. The third linear guide 31 extends along the vertical direction in FIG. 1 on the base 3 and is disposed on the sub-movement table 20 on the right side in FIG. 1 (see FIGS. 2B and 2C). The linear guide 31 includes a stator 32 fixed on the base 3 and a mover 33 slidably combined with the stator 32. A box-shaped ball screw box 36 is provided between the stator 32 of the third linear guide 31 and the auxiliary moving table 20. When the third linear guide 31 slides, the sub-movable table 20 can reciprocate with respect to the base 3 in the direction C (and C ′) in FIG.
[0013]
Here, the relationship of each direction of A, B, and C in the linear actuator 1 of the present embodiment will be summarized. The direction A (the moving direction of the mover 13 of the main moving table 10 and the first linear guide 11) and the direction C (the moving direction of the mover 33 of the sub moving table 20 and the third linear guide 31) are orthogonal to each other. I have. The direction B (the moving direction of the mover 23 of the second linear guide 21) is inclined at a small angle θ (about 6 °) counterclockwise in FIG. 1 with respect to the direction orthogonal to the direction A, that is, the direction C. I have.
The overall operation of the above-described linear guides 11, 21, 31 and the main and sub movable tables 10 and 20 will be described later in detail together with the operation of the sub movable table drive mechanism 30.
[0014]
The sub-movement-table drive mechanism 30 includes a motor (drive source) 41 including a servomotor or a stepping motor. The motor 41 is fixed on the base 3 with the support legs 42 in a state where the output shaft 41a is placed horizontally with the output shaft 41a facing the sub movable table 20 (the lower side in FIG. 1) (see FIG. 2C). The output shaft 41 a of the motor 41 is connected to a ball screw 45 via a coupling member (coupling) 43. Reference numeral 44 denotes a bearing box for the ball screw 45.
[0015]
The ball screw 45 has a screw shaft 46 and a nut 47. The screw shaft 46 is arranged vertically along FIG. 1 so as to be located on the same axis as the output shaft 41a of the motor 41. One end (upper end in FIG. 1) of the screw shaft 46 is connected to the connecting member 43, and the other end (lower end in FIG. 1) extends to the lower surface of the sub movable platform 20. On the other hand, the nut 47 is inserted into the above-mentioned ball screw box 36 and fixed integrally therewith.
[0016]
Next, the operation of the linear actuator 1 having the above-described configuration will be described. (1) When the main carriage 10 is moved in the direction A (when the motor 41 rotates forward)
When the motor 41 of the auxiliary carriage drive mechanism 30 is driven to rotate in the forward direction, the screw shaft 46 of the ball screw 45 connected to the output shaft 41a of the motor 41 also rotates in the same direction. Then, the nut 47 screwed to the screw shaft 46 moves in the direction C (the side away from the motor 41). At the same time, the mover 33 of the third linear guide 31 slides in the direction C via the ball screw box 36 to which the nut 47 is fixed, and the sub-movement table 20 moves in the direction C.
[0017]
When the sub moving table 20 moves in the C direction, the mover 23 of the second linear guide 21 fixed to the sub moving table 20 also moves in the C direction. At the same time, the stator 22 of the second linear guide 21 fixed to the main carriage 10 moves in the direction A. As a result, the main carriage 10 to which the stator 22 of the second linear guide 21 is fixed is pushed to the left in FIG. 1 and moves in the direction A along the first linear guide 11.
[0018]
At this time, assuming that the amount of movement of the sub-mobile 20 in the direction C is L, the amount of movement X of the main mobile 10 in the direction A is X = L · tan θ from tan θ = X / L.
(See the triangle in FIG. 1). In the present embodiment, since the angle θ is set to about 6 ° as described above,
tanθ ≒ 0.1
As a result, the movement of the ball screw 45 (that is, the movement amount L) for moving the sub-movement table 20 can be reduced to 1/10 to be the movement of the main carriage 10 (that is, the movement amount X). Therefore, the positioning resolution of the main moving table 10 can be set to a submicron level.
[0019]
(2) When the main carriage 10 is moved in the direction A '(when the motor 41 rotates in the reverse direction)
When the motor 41 of the sub-mobile unit driving mechanism 30 is driven to rotate in the opposite direction to that described above, the screw shaft 46 of the ball screw 45 also rotates in the same direction, and the nut 47 moves in the direction C ′ (toward the motor 41). At the same time, the mover 33 of the third linear guide 31 slides in the C 'direction, and the sub-movement table 20 moves in the C' direction. When the sub-mobile 20 moves in the direction C ', the mover 23 of the second linear guide 21 also moves in the direction C'. At the same time, the stator 22 of the second linear guide 21 moves in the direction A ', and the main carriage 10 is pushed rightward in FIG. 1 to move in the direction A' along the first linear guide 11. Also in the case of this (2), similarly to the case of the above (1), the movement of the ball screw 45 for moving the sub-movement table 20 can be reduced to 1/10 to be the movement of the main movement table 10.
[0020]
[Second embodiment]
FIG. 3 is a plan view showing a linear actuator according to a second embodiment of the present invention.
4A is a partially omitted left side view of the linear guide of FIG. 3, FIG. 4B is a front view, and FIG. 4C is a partially omitted right side view.
The linear actuator 2 shown in FIGS. 3 and 4 has a base 5 substantially similar to the linear actuator 1 described in the first embodiment, and a main moving table 50, a sub moving table 60, and a sub moving table on the base 5. A drive mechanism 70 is provided. The main difference between the linear actuator 1 and the linear actuator 1 is that the center of the sub-movement table 60 and the sub-movement table driving mechanism 70 are inclined with respect to the moving direction of the main movement table 50. That is.
[0021]
The main moving table 50 of the linear actuator 2 is mounted via two first linear guides (preload rolling linear bearings) 51 parallel to each other (see FIGS. 4A and 4B). Both linear guides 51 include a stator 52 fixed on the base 5 and a mover 53 slidably combined with the stator 52. The main carriage 50 is hung and fixed on the mover 53 of the two first linear guides 51. As the first linear guides 51 slide, the main carriage 50 can move relative to the base 5 in the direction A (and A 'direction) in FIG.
[0022]
The sub movable platform 60 is mounted on the main movable platform 50 via a second linear guide 61. The second linear guide 61 is disposed on the main carriage 50 along a direction orthogonal to the direction A (the sliding direction of the first linear guide 51). The linear guide 61 includes a stator 62 fixed on the main moving table 50 and a movable member 63 slidably combined with the stator 62. The sub movable platform 60 is fixed on the mover 63 of the second linear guide 61. When the sub-mobile unit 60 is moved by the operation of the sub-mobile unit driving mechanism 70, the mover 63 of the second linear guide 61 also slides in the C (and C ') direction.
[0023]
The sub-movement-table driving mechanism 70 includes a third linear guide 71 (see FIGS. 4B and 4C). The third linear guide 71 includes a stator 72 fixed on the base 5 and a mover 73 slidably combined with the stator 72. Further, the sub-mobile unit driving mechanism 70 includes a motor (servo motor or stepping motor) 81 and a ball screw 85 similar to those of the first embodiment. The center of the third linear guide 71, the motor 81 and the ball screw 85 is inclined clockwise in FIG. 3 by an angle θ (about 6 °) with respect to the width center of the second linear guide 61.
[0024]
The third linear guide 71 is slidable in the above-described direction inclined by the angle θ (the CC ′ direction in FIG. 3). The motor 81 is fixed on the base 5 by a bearing box 82 (see FIG. 4C). The screw shaft 86 of the ball screw 85 is connected to the output shaft 81a of the motor 81 via a connecting member (coupling) 83. As in the first embodiment, the nut 87 of the ball screw 85 is inserted into a ball screw box 76 that connects the stator 72 of the third linear guide 71 and the auxiliary moving table 60, and is integrally fixed. The sub movable table 60 is arranged in a state of being inclined with respect to the main movable table 50 such that both sides (left and right sides in FIG. 3) are parallel to the CC ′ direction. When the third linear guide 71 slides, the sub-movement table 60 can reciprocate in the direction C (and C ′) in FIG.
[0025]
Here, the relationship of each direction of A, B, and C in the linear actuator 2 of the present embodiment will be summarized. The direction A (the moving direction of the mover 53 of the main moving table 50 and the two first linear guides 51) and the direction B (the moving direction of the mover 63 of the second linear guide 61) are orthogonal to each other. The direction C (the moving direction of the mover 73 of the third linear guide 71) is inclined clockwise in FIG. 3 by an angle θ (about 6 °) with respect to the direction orthogonal to the direction A, that is, the direction B.
[0026]
Next, the operation of the linear actuator 2 having the above-described configuration will be described. (1) When the main carriage 50 is moved in the direction A (when the motor 81 rotates forward)
When the motor 81 of the sub-movement-table drive mechanism 70 is driven to rotate in the forward direction, the screw shaft 86 of the ball screw 85 also rotates in the same direction, and the nut 87 moves in the direction C (the side away from the motor 81). At the same time, the mover 73 of the third linear guide 71 slides in the C direction, and the sub-movement table 60 moves in the C direction. When the sub movable platform 60 moves in the C direction, the mover 63 of the second linear guide 61 also moves in the C direction. At the same time, the mover 53 of the first linear guide 51 slides with respect to the stator 52, and the main moving table 50 is pushed and moved in the direction A in FIG.
[0027]
At this time, assuming that the amount of movement of the sub movable table 60 in the direction C is L, the amount of movement X of the main movable table 50 in the direction A is X = L · sin θ from sin θ = X / L.
(See the triangle in FIG. 3). In the present embodiment, since the angle θ is set to about 6 ° as described above,
sinθ ≒ 0.1
Thus, the movement (ie, L) of the ball screw 85 that moves the sub-movement table 60 can be reduced to 1/10 to be the movement (ie, X) of the main movement table 50.
[0028]
(2) When the main carriage 50 is moved in the direction A '(when the motor 81 rotates in the reverse direction)
When the motor 81 of the sub-movement-table driving mechanism 70 is driven to rotate in the opposite direction to that described above, the screw shaft 86 of the ball screw 85 also rotates in the same direction, and the nut 87 moves in the direction C ′ (toward the motor 81). At the same time, the mover 73 of the third linear guide 71 slides in the C 'direction, and the sub-movement table 60 moves in the C' direction. When the sub-carrier 60 moves in the direction C ', the mover 63 of the second linear guide 61 also moves in the direction C'. At the same time, the mover 53 of the first linear guide 51 slides with respect to the stator 52, and the main carriage 50 is pushed and moved in the direction A 'in FIG. Also in the case of (2), similarly to the case of (1), the movement of the ball screw 85 for moving the sub-movement table 60 can be reduced to 1/10 to be the movement of the main movement table 50.
[0029]
As described above, in the linear actuators 1 and 2 of the first and second embodiments, since the positioning resolution of the main moving tables 10 and 50 can be set at a submicron level, high precision positioning resolution is required. The present invention can be applied to various apparatuses such as an image processing apparatus. Furthermore, since each linear guide of both actuators 1 and 2 has a low coefficient of friction and no backlash, it has high durability and can realize a straight operation without play with small power. In addition, since a so-called one-sided structure, which is required in a commonly used wedge-type operation reduction mechanism, is not required, the number of parts is small and the entire structure is simple.
[0030]
【The invention's effect】
As is clear from the above description, according to the present invention, it is possible to provide a linear actuator having advantages such as realization of high-precision positioning resolution, simple structure and inexpensive manufacturing.
[Brief description of the drawings]
FIG. 1 is a plan view showing a linear actuator according to a first embodiment of the present invention.
2 (A) is a partially omitted left side view of the linear guide of FIG. 1, FIG. 2 (B) is a front view, and FIG. 2 (C) is a partially omitted right side view. .
FIG. 3 is a plan view showing a linear actuator according to a second embodiment of the present invention.
4 (A) is a partially omitted left side view of the linear guide in FIG. 3, FIG. 4 (B) is a front view, and FIG. 4 (C) is a partially omitted right side view. .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Linear actuator 3 Base 10 Main slide 11 First linear guide 12 Stator 13 Mover 20 Sub mover 21 Second linear guide 22 Stator 23 Mover 30 Sub mover drive mechanism 31 Third linear guide 32 Stator 33 mover 36 ball screw box 41 motor 45 ball screw 46 screw shaft 47 nut 2 linear actuator 5 base 50 main moving table 51 first linear guide 52 stator 53 mover 60 auxiliary moving table 61 second linear guide 62 fixed Child 63 mover 70 sub-mobile unit driving mechanism 71 third linear guide 72 stator 73 mover 76 ball screw box 81 Data 85 Ball screw 86 Screw shaft 87 Nut

Claims (1)

Base and
A main carriage mounted on the base so as to be movable in the A direction via a first linear guide (preload rolling linear bearing);
A sub-mobile mounted on the main mobile via a second linear guide so as to be movable in the B direction with respect to the main mobile;
A servo motor or a stepping motor for moving the sub-movement table in the C direction with respect to the base via a third linear guide, and a sub-movement table driving mechanism including a ball screw rotated by the motor;
With
By moving the sub-movement table in the C direction, the mover of the second linear guide fixed to the sub-movement table is moved in the B direction. Moving the stator of the second linear guide in the direction A, thereby moving the main moving table in the direction A;
A linear actuator, wherein the amount of movement L of the sub-mobile unit in the C direction is reduced to a fraction or less to be the amount of movement of the main mobile unit in the A direction.

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